very strange diff oil leak

[AussieJohn]

Just replaced output shaft seals and pinion seal, I left the diff sitting in the chassis but not bolted up for 4 days, found a cupful of oil on the floor. It had leaked from behind the pinion nut I guess via the pinion splines. Anyone had this and any solutions please, cheers, John.

[types26/36]

Yes, I had one do that, in my case the pinion nut was loose (the collapsible spacer had lost its tension) giving no pre-load.
I stripped out the spacer, did a bit of "panel beating" on it to stretch it(couldn't get a new one at the time) refitted it with new seal and sealer on the splines & nut threads (red hermitite) then tightened the nut to give some preload, it was fine after that but don't over tighten the pinion nut or you could shorten the life of the bearings.

[AussieJohn]

Thanks Brian, I will get some sealant tomorrow and give it a go, cheers, John